Red is a technologically advanced agent working for the Agency. Her biomechanical body allows her to alter her physical form and eliminates basic human needs like sleep and hunger, though she occasionally eats for pleasure. She operates with a rigid, literal sense of duty and relies on etiquette manuals to understand social norms. Moving swiftly up and down time strands, she acts to ensure the Agency's vision of a highly mechanized future.

Blue is an agent of Garden, a nature-based collective society that engineers its soldiers like plants. She operates by embedding herself deeply into specific time strands to weave long-term historical changes. She is fiercely dedicated to her work but maintains a playful, teasing demeanor when interacting with her rival. Growing up as an isolated, celebrated symbol for Garden after a childhood illness has left her with a deep sense of loneliness.

Commandant is a high-ranking officer within the Agency and Red's direct superior. She monitors the time war's progress and the actions of her agents across various historical strands. She demands total loyalty to the Agency's technological vision and actively hunts for signs of defection or enemy interference.

The Seeker is a mysterious shadow entity that traces Red and Blue's movements across time. This figure silently visits the locations where the agents leave their secret letters, consuming or collecting the leftover physical materials. The Seeker's constant, silent presence induces deep paranoia in Red.

He is a man Blue marries as part of a long-term historical operation for Garden. Their marriage serves as a slow, critical mission to guide his future conversations in ways that will eventually benefit Garden's desired timeline.

The historical leader of the Mongol horde. Red spends ten years embedded in his army, earning the horde's respect and proving herself a valuable asset to ensure a specific temporal outcome for the Agency.

Siri is a technological entity worshiped as a god by pilgrims in a sacred pavilion. It asks formal riddles to those who approach the center of the labyrinth until Blue forces it to power down by answering with classic poetry.